Recently I had a paper accepted and published in the European Journal of Sports Science. The aim of this paper was to examine the relationship between regular game-related caffeine consumption on sleep after an evening Super Rugby game. Although the benefits of caffeine on physical performance are well documented, the impact on sleep from the use of caffeine for performance is not well understood or researched in sport. In particular within professional rugby union.

How did we do it? So what did we find?  

On the night of the game, players went to bed 3 hours later and had on average 90 mins less sleep than other nights and four players did not sleep after the game. Caffeine concentrations were greater than pre-game levels in 17 players (Pre-game 0.40 ?g/mL vs Post-game 2.77 ?g/mL; p <0.001). This increase in caffeine associated with an increase in the time to fall asleep and a decrease in the overall sleep quality.

Takeaways

• Caffeine consumption in the 4-6 hours of sleep may have a negative impact on sleep.
• Even if players have the next day off to recover, they do not compensate for this negative impact on sleep, thereby reducing sleep duration.
• Individuals or athletic staff may need to delay training start times on the post-competition days to support an increase in sleep duration in order to support recovery.
• A caffeine consumption strategy for rugby players and athletes based upon pharmacokinetics of caffeine and timing of the game may prove beneficial for performance whilst minimising the subsequent negative effects on time to fall asleep and sleep duration.

So, we asked 20 elite rugby union players from the Western Force to wear a wrist-activity monitor (Readiband) to measure sleep for three days before, three days after and on the night of an evening Super Rugby game (19:00–21:00). The players consumed caffeine as they normally would. To measure the caffeine levels we took saliva samples before the game and after the game. This allowed us to quantify the change (+/-) in individual caffeine levels.

Caffeine use in a Super Rugby game and its relationship to post-game sleep.Eur J Sport Sci. 2018 Feb 12:1-11. doi: 10.1080/17461391.2018.1433238. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/29431593